Quantification of the flexural rigidity of endovascular surgical devices using three-point bending tests

Endovascular surgical procedures require the navigation of catheters and wires through the vasculature to reach distal target sites. Quantitative frameworks for device selection hold the potential to improve the tracking of endovascular devices through vascular anatomy by personalizing the device flexural rigidity to an individual's anatomy. However, data are lacking to facilitate this technology, in part because typical endovascular devices have intricate spatial variations in mechanical properties that are challenging and tedious to quantify repeatably. We therefore developed a three-point bend test methodology using a custom rig and applied it to measure lengthwise flexural rigidity profiles of endovascular devices that are used to target the cerebral vasculature. The methodology demonstrated high repeatability and was able to characterize transition zones. We applied the methodology to generate the first comprehensive, quantitative library of device flexural rigidities, spanning guidewires, intermediate guides, and long sheaths. We observed that these three classes of device have properties that fall into distinct ranges. Additional plots examining relationships between flexural rigidity, device diameter, and length revealed application-specific trends in flexural properties. This methodology and the data allow for standardized characterization and comparisons to aid device selection, and have the potential to both enhance surgical planning and inform future innovation.